IsoCubeSim is my cuboid (LxMxN) simulator, with a few variations which do other things. It was specifically designed to be used for computer speedcubing - before the era of more complex keyboard-controlled cube sims, many of the world speed records were set on this program. In fact, many of the overall records for very large cubes are still on this sim. IsoCubeSim and IsoSupercubeSim have the following features (the others are a bit older):

IsoCubeSim is distributed as a self-executable .jar file. You should be able to run it like an application, if you have Java installed. Because a certain browser doesn't handle .jar files correctly, I've included each one in a .zip file. Here are the versions available for download: